FIG. 1 is a block diagram of a conventional network 10. The network 10 includes a computer system 12 which is coupled to a first fabric connectivity switch 14 by one optical cable 16 and is coupled to a storage device 18 by another optical cable 20. The storage device 18 is also coupled to a second fabric connectivity switch 22 by an optical cable 24. Finally, the fabric connectivity switch 14 is coupled to the second switch by an optical cable 26.
Simulating cable failures in a network such as network 10 is critical to development, testing, and quality assurance for devices utilized in the network. Conventional approaches to simulating cable failures include simulation via cables being manually pulled, providing expensive optical attenuators, or utilizing the existing switches that are provided for fabric connectivity and not for the simulation of cable failures. Each of these conventional approaches is described herein below.
Manual Simulation of Cable Failures
Simulating cable failures manually is not an adequate approach because manual simulations are both inaccurately timed and also expensive to simulate over a period of time because persons must be employed to actually pull the cable. In human terms, the timing can not be much more accurate than within 0.5 seconds. Proper cable testing should be able to constantly provide a length of failure to within 0.001 seconds or better. Also, to stimulate hundreds of cable failures, one or more persons must work night and day. The method and system in accordance with the present invention, in contrast, allows for cable failures to be simulated automatically during any time period and at any time, thereby freeing up human and capital resources.
Utilization of Attenuators for Simulating Cable Failures
Attenuators can also be utilized for simulating cable failures. An attenuator can provide an automated method for cable failures, but its simulation functions by turning down the level of light until it is a very small percentage of the proper signal. This is not as accurate as complete loss of light which the method and system in accordance with the present invention provides. Attenuators are also very expensive devices that are used for many other purposes than just cable failures.
Utilization of Fabric Connectivity Switches for Simulating Cable Failures
A third conventional approach is to utilize fabric connectivity switches for simulating cable failures and determining optical connectivity. Fabric connectivity switches utilized for this purpose are typically very expensive. The ports on the fabric connectivity switch can be taken offline, thus simulating a cable failure. These switches are not intended for such test operations. Also, a fabric connectivity switch is a device to be tested in this environment. Using the fabric connectivity switch to simulate its own cable failure could alter the outcome and may not give accurate information. This environment is also intelligent so that if the fabric connectivity switches are connected, trying to simulate a cable failure between an adapter and a disk with a fabric connectivity switch is impossible.
Accordingly, what is needed is a system and method for simulating cable failures when testing optical devices which is less expensive than current approaches and can be automated. The present invention addresses such a need.